Since three-dimensional whole body scanners were first introduced in the 1990's, many countries have invested lots of money and efforts in related researches and tests. In early researches, methods for landmark extraction still required human intervention. Nowadays, it is highly automated with the assistance of computer technology. In addition, in order to make this technology feasible for the industry, the needs for processing data more efficiently, accurately, and stably are also emphasized.
In the initial stage, most researches employed the method of pre-marking. Color markers are put on certain parts of the subject's body before scanning, and then the locations of these markers are identified manually on the computer screen. The CAESAR (Civilian American and European Surface Anthropometry Resource) project, in which a large-scaled three-dimensional anthropometric database of over 5,000 subjects was constructed across six countries in the Europe and the US, applied this technology to facilitate accurate measurements. However, even though this method yields higher identification rates, it is not time-efficient, especially when used in large projects or surveys. In these cases, the progress of data analysis often lags far behind that of scanning. Therefore, it requires considerable efforts after scanning. Later on, some researches developed methods for identifying pre-marked color markers by using their color information and the technology of image processing. Although these methods had indeed shorten the time for identifying color markers, it was still unable to shorten the time for manual pre-marking and to avoid human errors that is derived from this task.
In later stages, researchers attempted to develop methods for landmark extraction based on the shape of human body. These methods require no more needs for pre-marking before scanning, and in hence shorten the processing time and avoid the effects of human errors. These methods depict the human body in a geometric way, such as the technique of curve fitting and surface reconstruction, in order to make it easier and faster to find the locations of the features. Many software vendors, such as Human Solutions from Germany, Cyberware and [TC]2 from US, have developed new products for the use of three-dimensional body scanner using these methods. However, individual variations in body shapes inevitably reduce the identification rate of these methods, especially when they are applied to a subject of the race that is not originally designed for. Therefore, there are still difficulties in extracting landmarks successfully and accurately.
Hence, to develop a practical method for landmark extraction is an important issue that the industry concerned. For these purposes, this invention was developed according to experiences in related areas.